Encoding method on basis of polar code in order to support HARQ, and wireless device using same

Abstract

An encoding method on the basis of a polar code in order to support an HARQ according to the present embodiment comprises the steps of: configuring, an input vector for retransmission, which has a length of N and is applied to a mother matrix predetermined on the basis of a polar code, by a wireless device, wherein the input vector is defined on the basis of a first index set for an optimized position of an information bit having a length of K, a second index set for a position of a bit to be punctured among encoded bits generated on the basis of the mother matrix, and a third index set for a position of at least one unknown frozen bit associated with an information copying scheme; and performing encoding on the basis of the input vector and the mother matrix, by the wireless device.

What is claimed is: 
     
       1. A method of performing encoding based on a polar code to support hybrid automatic repeat request (HARQ), the method comprising:
 configuring, by a wireless device, a length-N input vector (where N is a natural number) applied to a mother matrix predetermined based on the polar code; 
 defining the input vector based on a first index set for an optimized location of a length-K information bit (where K is a natural number), a second index set for a location to be punctured among coded bits generated based on the mother matrix, and a third index set for a location of at least one unknown frozen bit associated with an information copy scheme; 
 encoding, by the wireless device, length-N bits based on the input vector and the mother matrix; 
 determining, by the wireless device, at least one transmission bit, among the length-N encoded bits, based on the second index set; and 
 transmitting, by the wireless device, the at least one transmission bit to a second wireless device. 
 
     
     
       2. The method of  claim 1 ,
 wherein the input vector is defined as {u0, u1, . . . , uN−1}, 
 wherein a location index for the input vector is defined as {0, 1, . . . , N−1}, and 
 wherein the first index set to the third index set are defined based on {0, 1, . . . , N−1}. 
 
     
     
       3. The method of  claim 2 , wherein, when N is ‘8’, decoding is performed based on the order of predetermined location indices {0}, {4}, {2}, {6}, {1}, {5}, {3}, {7}. 
     
     
       4. The method of  claim 2 , wherein the input vector is configured to include all of length-I second information bits (where I is a natural number) for previous transmission, and the number of elements included in the second index set is configured to be less than that in the previous transmission. 
     
     
       5. The method of  claim 4 , wherein, when K and I are both ‘3’, when the first index set is {a, b, c} and the optimized location index for the second information bit for the previous transmission is {d, b, c}, the information included in the location index {d} is copied to a location index which is decoded before the location index {d} based on the information copy scheme. 
     
     
       6. The method of  claim 5 , wherein, when the location index {d} is copied to the location index {a}, the third index set of the input vector for HARQ retransmission includes {d}. 
     
     
       7. The method of  claim 1 , wherein the mother G N  is defined in a form of a Kronecker product of a base matrix F as follows:
     G   N   =F   ⊗N , 
 when the base matrix F is defined as follows: 
 
       
         
           
             
               F 
               = 
               
                 
                   [ 
                   
                     
                       
                         1 
                       
                       
                         0 
                       
                     
                     
                       
                         1 
                       
                       
                         1 
                       
                     
                   
                   ] 
                 
                 . 
               
             
           
         
       
     
     
       8. The method of  claim 7 , wherein the mother matrix has a size of N×N (where N is a natural number, and N is 2{circumflex over ( )}n (where n is a natural number). 
     
     
       9. The method of  claim 8 , wherein the second index set is defined as follows:
     B   {dot over (p)}       N         N   ={0,1 , . . . , N   } for some integer    N = 2   n    with 1 ≤ n ≤n.  
 
 
     
     
       10. The method of  claim 1 , wherein an input vector of a location for the second index set includes a frozen bit having a predetermined value. 
     
     
       11. A wireless device for performing encoding based on a polar code to support hybrid automatic repeat request (HARQ), the wireless device comprising:
 a radio frequency (RF) unit transmitting and receiving a radio signal; and 
 a processor operatively coupled to the RF unit, wherein the processor is configured to: 
 configure a length-N input vector (where N is a natural number) applied to a mother matrix predetermined based on the polar code; 
 define the input vector based on a first index set for an optimized location of a length-K information bit (where K is a natural number), a second index set for a location to be punctured among coded bits generated based on the mother matrix, and a third index set for a location of at least one unknown frozen bit associated with an information copy scheme; 
 encode length-N bits based on the input vector and the mother matrix; 
 determine at least one transmission bit, among the length-N encoded bits, based on the second index set; and 
 transmit the at least one transmission bit to a second wireless device. 
 
     
     
       12. The wireless device of  claim 11 ,
 wherein the input vector is defined as {u0, u1, . . . , uN−1}, 
 wherein a location index for the input vector is defined as {0, 1, . . . , N−1}, and 
 wherein the first index set to the third index set are defined based on {0, 1, . . . , N−1}. 
 
     
     
       13. The wireless device of  claim 12 , wherein, when N is ‘8’, decoding is performed based on the order of predetermined location indices {0}, {4}, {2}, {6}, {1}, {5}, {3}, {7}. 
     
     
       14. The wireless device of  claim 12 , wherein the input vector is configured to include all of length-I second information bits (where I is a natural number) for previous transmission, and the number of elements included in the second index set is configured to be less than that in the previous transmission. 
     
     
       15. The wireless device of  claim 14 , wherein, when K and I are both ‘3’, when the first index set is {a, b, c} and the optimized location index for the second information bit for the previous transmission is {d, b, c}, the information included in the location index {d} is copied to a location index which is decoded before the location index {d} based on the information copy scheme. 
     
     
       16. The wireless device of  claim 15 , wherein, when the location index {d} is copied to the location index {a}, the third index set of the input vector for HARQ retransmission includes {d}. 
     
     
       17. The wireless device of  claim 11 , wherein the mother method matrix GN is defined in a form of a Kronecker product of a base matrix F as follows:
     G   N   =F   ⊗N    
 when the base matrix F is defined as follows: 
 
       
         
           
             
               F 
               = 
               
                 
                   [ 
                   
                     
                       
                         1 
                       
                       
                         0 
                       
                     
                     
                       
                         1 
                       
                       
                         1 
                       
                     
                   
                   ] 
                 
                 . 
               
             
           
         
       
     
     
       18. The wireless device of  claim 17 , wherein the mother matrix has a size of N×N (where N is a natural number, and N is 2{circumflex over ( )}n (where n is a natural number). 
     
     
       19. The wireless device of  claim 18 , wherein the second index set is defined as follows:
     B   {dot over (p)}       N         N   ={0,1 , . . . , N   } for some integer    N = 2   n    with 1 ≤ n ≤n.